1000 is a very large number for children working in Year 3 and one which is difficult to imagine the size of. The sheet asks how many different ways can two numbers be added to make 1000, using only whole hundreds.To be able to do this children need to be confident with their numbers up to 10 and be able to know which pairs of numbers add up to 10.

As an investigation it is very similar to asking how many ways can 100 be made only using whole tens.